module.php: Be more paranoid when verifying paths.
module.php: Be more paranoid when verifying paths.

Cannot see a way that this can be used to escape the module www
directory, but being more specific in the test won't hurt.

rchavik/simplesamlphp,rchavik/simplesamlphp,rchavik/simplesamlphp,rchavik/simplesamlphp